change hostname button

static/app.js

@@ -1309,6 +1309,13 @@ let hostNameText = document.getElementById("host-name");
 hostNameBtn.addEventListener("click", () => {
   hostNameText.innerText = hostNameInput.value;
   localStorage.setItem("hostName", hostNameText.innerText);
+  
+   data = {hostname:hostNameText.innerText}
+  
+  fetch("/hostname", {
+      method: "POST",
+      body: JSON.stringify(data),
+    });
 });
 
 // change brightness